Thoughts on these scanmaster readings

[BlackOut89]

Scanmaster readings*

1986 GN 101,XXX miles. Mods are...30lb injectors, flowmaster exhaust, poston headers, smc alky kit, turbo tweak chip, running like 25lb boost.

Idle: * * * * * * * * * * * * * * * * **

O2: 738-785*
AF: 04
LB: 34
INT: 128
BL: 141
CLT: 171
ATS: 69
RPM: 725
TPS: .44
IAC: 29-32

40mph:

AF: 13-16
LB: 55
INT: 129-136
BL: 132
ATS: 69
IAC: 79


Jumped on it a little and it started to knock close to WOT I read 7.3 of retard so I let out. But I noticed this is intermittent because there I times when I lay into and I only read .9 retard. Let me know what you guys think.

Thanks, Steve

 

[SS/GN]

What is fuel pressure,are you getting tire spin???Is this knock in high gear??

Kevin

 

[RIFF RAFF]

I think you have a vacume leak somewhere .. Blm should never be out of range of ten between int and blm at idle . So with a int of 128 your blm should be no higher then 138 .. Look for a leak ..

 

[BlackOut89]

Well the vacume lines are a good start thanks oil man, i hope to either hunt these down tomorrow or later in the week. and SS/GN my fuel pressure i believe is 38lb? idk i will warm the car up and double check and give you a solid number. And as far as the chattering i am hearing i think we have narrowed it down to an exhaust leak where the downpipe meets the rest of the exhaust, so i will get that sealed up and see if that takes care of it.

 

[750H.P.V6]

I think you have a vacume leak somewhere .. Blm should never be out of range of ten between int and blm at idle . So with a int of 128 your blm should be no higher then 138 .. Look for a leak ..

I'm confused by this. integrator is short term fuel correction and block learn is long term fuel correction. The integrator drives the block learn. If the integrator is less than 128 the block learn will go down conversely if the integrator is higher than 128 the block learn will go up. I agree the block learn is somewhat high at idle but the MAF reading is low which will cause this.

Neal

 

[RIFF RAFF]

i'm confused by this. Integrator is short term fuel correction and block learn is long term fuel correction. The integrator drives the block learn. If the integrator is less than 128 the block learn will go down conversely if the integrator is higher than 128 the block learn will go up. I agree the block learn is somewhat high at idle but the maf reading is low which will cause this.

Neal

i was taught to use a target number of 128 for both at hot idle . And if my target number is 128. Blm should be within a range of ten high or low so 117 would be to low 139 too high anywhere in between there the car should run fine .. Right now my car is 131 hot idle and i know i have a small leak at the tb .. I didnt catch the maff reading the first time .. The blm just stood out ..

 

[groumoutis]

The best way I have found to find vac leaks is to use a golf tee to plug vac lines one at a time. Just make sure you plug the right side of the vac line.

 

[usetaboost]

I would lower the tps to .41 with key off. You would have to have a MAJOR exhaust leak to move blm. Hell I had 3 big leaks before the 02 and the blm still was on 128. I'm not saying you don't have a leak, but with the tps at .44 you are riding the edge of a tps high condition.

 

[TurboDave]

Scanmaster readings*

1986 GN 101,XXX miles. Mods are...30lb injectors, flowmaster exhaust, poston headers, smc alky kit, turbo tweak chip, running like 25lb boost.

Idle: * * * * * * * * * * * * * * * * **

O2: 738-785*
AF: 04
LB: 34
INT: 128
BL: 141
CLT: 171
ATS: 69
RPM: 725
TPS: .44
IAC: 29-32

40mph:

AF: 13-16
LB: 55
INT: 129-136
BL: 132
ATS: 69
IAC: 79


Jumped on it a little and it started to knock close to WOT I read 7.3 of retard so I let out. But I noticed this is intermittent because there I times when I lay into and I only read .9 retard. Let me know what you guys think.

Thanks, Steve

Nothing terrible, however, I see that your AF is a little on the low side. I always look for a 6 (hot idle) as ideal, I would accept a 5, but a reading of 4 would concern me. This is likely why your BLM is a little on the high side. The 4 would lean things out a little and the BLM is trying to compensate.

So, this raises the question..... What's with the MAF? Is it original? is it a reman? etc.

 

[TurboDave]

I think you have a vacume leak somewhere .. Blm should never be out of range of ten between int and blm at idle . So with a int of 128 your blm should be no higher then 138 .. Look for a leak ..

Your assumptions about the relationship between INT and BLM are a bit confused.

May I suggest you read this article I posted several years ago explaining the operation of INT and BLM.

Block Learn Multiplier and Integrator

 

[RIFF RAFF]

I am always willing to learn. So i will take a look .. Thanks

 

[usetaboost]

are you still running the factory maf hose? maybe there's a leak in the intake track somewhere

 

[BlackOut89]

are you still running the factory maf hose? maybe there's a leak in the intake track somewhere

yeah as far as i know i am. i am planing on taking the MAF out and inspeting it for damage or possibly clogged. if not i will start testing the MAF sensor itslef because it could be intermittently failing and i will also be inspecting all the vacume lines and so forth. So it sounds like a have some work to do this weekend id say haha. i will keep everyone updated on what i find and again a appreciate everyones input. keep em comin!

 

[usetaboost]

You better check that maf hose for a hole before get too crazy buying stuff

 

[BlackOut89]

Yeah, no im not going to be buying anything until I find out the source. I am going to be doing a lot if worn this weekend testing and hunting this down. But first thing I'll do is check that MAF hose and I'll let you know what I find.

 

[usetaboost]

bring the tps down while you're at it.

 

[BlackOut89]

hey everyone sorry it has taken me so long to reply back to the post, i have been crazy busy then was at Bowling green for the GS Nationals. Anyways i have gotten my INT anf BL numbers within 10 of eachother by adjusting my fuel pressure. But i still believe my MAF is malfunctioning and still am knocking under high boost(intermitent). This satursday i finally have free time so all my focuse is on the GN, i am going to test the MAF see what i get. i also noticed recently that my O2 readings drop to zero and stay there for a minute...any thoughts on that? it just started doing it.

 

[ikle]

SS/GN my fuel pressure i believe is 38lb?

I thought the recommended fuel pressure for TT chips is 43lbs.vac line off

 

[BlackOut89]

SS/GN my fuel pressure i believe is 38lb?

I thought the recommended fuel pressure for TT chips is 43lbs.vac line off

It is and thats what i set it to now. it was weird because i was smelling rich but my scan master was reading lean conditions. but this is also the reason why i think my MAF is malfunctioning.

 

[BlackOut89]

Also i think i just figured out my O2 readings and why they are going to zero(brain fart ) I have a TT chip and i believe they make the O2 open loop correct??